Every fume extractor gets a score from 0 to 100% built from six factors, which maps onto the 5-point rating shown on the site (a 0% score would be 1.5 stars; a perfect score, 5). Each factor is scored against fixed reference points, not against the other products in the list, so adding a new model never moves another model’s rating. Extractors are grouped as compact, under 120 CFM, and high-flow, 120 CFM and up, and use the same scale in both groups.
| Factor | Measures | Weight |
|---|---|---|
| Value | price per CFM of airflow | 25% |
| Airflow | top published airflow; unpublished scores 0 | 25% |
| Filtration | activated carbon, true HEPA and a prefilter | 20% |
| Noise | top published noise level | 10% |
| Features | hose or arm, speed control, filter alarm, remote, ESD safety, extra intakes, casters and light | 10% |
| Warranty | warranty length | 10% |
Chemical safety is not scored
An extractor’s filters suit only what they are made to catch. HEPA filters trap particles and do nothing for vapors; activated carbon absorbs many odors and vapors but holds some poorly, and it can saturate without any visible change. These rankings score published specs only. The filtration factor counts which stages a product has, not how well they hold any particular substance, and no score here means a product is safe for a given chemical.
Where the numbers come from
Airflow, filters, noise, features and warranty come from the maker’s spec sheet, brochure or product copy, including the maker’s own copy on a retail listing. Airflow published in m³/h or m³/min is converted to CFM. Where a maker’s own figures conflict, such as a title that gives one noise level and a description that gives another, the figure is left out rather than guessed. Prices are checked at the stores each page links to, and the lowest is used.
The factors
Value is the current price divided by the airflow, in dollars per CFM, on a log scale, so halving the price always counts the same. $8 per CFM scores zero and $0.75 per CFM full marks.
Airflow is the top airflow the maker publishes, on a log scale: 20 CFM scores zero and 300 CFM full marks. Fan-type absorbers often state free-air flow, and hose-type extractors usually state airflow without the hose’s losses, so treat close figures as roughly equal.
Filtration is 40% for an activated carbon stage, 40% for a true HEPA stage (H13 or better, or 99.97% at 0.3 micron), and 20% for a separate prefilter. A HEPA stage of a lower or unstated grade, such as H11, counts 20%. A carbon or HEPA filter sold as an option counts 20%, since it costs extra.
Noise is the top noise level the maker publishes: 70 dB scores zero and 45 dB full marks.
Features is 20% for a hose, arm or duct that brings the intake to the work, 20% for adjustable airflow, 20% for a filter alarm or indicator, 10% for a remote, 10% for an ESD-safe build, 10% for two or more intakes, 5% for casters and 5% for a work light.
Warranty is the maker’s warranty: none scores zero and 3 years full marks.
What isn’t scored
Hose length, power, size, weight and release date are listed but not scored.
Missing data
If a minor figure isn’t published, that factor gets the neutral middle score (50) and the product page marks it as estimated. Features and filtration score neutral only when none of them is published; a feature or filter stage the maker doesn’t mention otherwise counts as absent. Two exceptions. Airflow is what separates these products most, so a product with no published airflow scores zero for both airflow and value, marked estimated. And a maker that doesn’t publish a warranty gets no warranty counted, so that factor scores zero and is marked estimated.
Ties and discontinued models
Products are ranked by score within each group. Discontinued models stay listed but rank below every current model and can be hidden with the “Hide discontinued” filter.